This invention relates to the field of medical devices and, in particular, devices for gripping small diameter shafts used in medical applications. More precisely, the invention relates to a device for securely gripping a guide wire or hollow tube for a catheter.
In an angioplasty procedure, a guide wire is inserted into a patient's artery, and the guide wire is maneuvered to a stenosis or location of arterial blockage. Once the guide wire is in position across the blockage, a balloon catheter is advanced over the guide wire across the stenosis. The balloon catheter is then inflated to relieve the arterial constriction, deflated and then ultimately removed from the artery.
The maneuvering of a guide wire through the tortuous anatomy of the arterial system and across a lesion at the point of stenosis requires an operator to carefully "steer" the guide wire. This is accomplished by rotating the guide wire as it is advanced distally, so that a bent distal tip on the guide wire can be directed into the appropriate arterial branches. Because a typical guide wire is formed from a small diameter wire, it is difficult for the operator to grasp securely, and accordingly, it is difficult to control the degree of rotation thereof. Medical device manufacturers currently provide a variety of so called "guide wire gripping devices", or "torquers", or "handles" for use in gripping and manipulating the wires, but they all suffer from one or more deficiencies.
One example of such gripping devices is disclosed in Mar, U.S. Pat. No. 4,726,369, and is of a cylindrical body of resilient material with a slit in which the guide wire is received. An outer sleeve encircling the resilient body holds the slit closed over the wire. The major deficiency of this device is that it slips on the guide wire (both longitudinally and torsionally) and therefore prevents any direct correlation between rotation of the device and rotation of the guide wire.
Another example is shown in Auth, U.S. Pat. No. 4,829,999, which discloses a spring loaded gripping device to provide a more positive grip on the guide wire. The Auth patent device has a cylindrical body made of elastic material that has a longitudinal slot for receiving the guide wire. Handles are provided on either side of the slot for forcibly spreading the slot to receive the guide wire. The handles make the device awkward to manipulate, and the device also slips on the guide wire as torque is applied to the device.